Multicircuit rotary electrical connector

ABSTRACT

A unitary multicircuit rotary electrical connector comprises a pair of terminal boards of insulation material in the form of substantially parallel spaced discs and means for mounting the boards for relative rotation, each of the boards having a plurality of spaced contact terminals arranged approximately in a circle with the groups of contact terminals of one of the boards at a greater radius than those of the other of the boards. The connector further comprises a plurality of flat flexible multiconductor ribbons preformed approximately in annular form and terminating at each end in a plurality of terminal contacts spaced to register with a group of contact terminals, the terminal contacts at one end of each of the ribbons being electrically connected to a group of terminals of one of the boards and the terminal contacts at the other end thereof being electrically connected to a group of terminals of the other of the boards and each ribbon being of a length to form an U-shaped loop between the boards, the ribbons being substantially equally spaced about the axis of rotation.

United States Patent [72] Inventor [2i Appl. No. [22] Filed [45] Patented [73] Assignee Joseph P. Mangan Whltestone, N.Y.

Sept. 29, 1969 Aug. 3, 1971 Aeroflex Laboratories Incorporated [54] MULTICIRCUIT ROTARY ELI'KITRICAL coNNncron 4Claimc,2DnwingFip.

52 u.s.c1. 339/5, 174/685 51 1m.c1 ..H0lr39/00 so FieldotSearcli 174/86; 339/5, 3 s, 17 r, 176 MP; 191/12 156 ReIerencesClted UNITED STATES PATENTS 3,028,445 4/1962 Hurley .1 3s9/17x 3,251,955 5/1966 Erickson 191/12 FOREIGN PATENTS 869.275 5/1961 GreatBritain 174/86 OTHER REFERENCES Electronic Design" publication page 145 10-12-60 page l45 (advert. of Hughes) (copy in 339-17 F) Primary Examiner-Richard E. Moore Attorney-Laurence B. Dodds ABSTRACT: A unitary multicircuit rotary electrical connector comprises a pair of terminal boards of insulation material in the form of substantially parallel spaced discs and means for mounting the boards for relative rotation, each of the boards having a plurality of spaced contact terminals arranged approximately in a circle with the groups of contact terminals of one of the boards at a greater radius than those of the other of the boards. The connector further comprises a plurality of flat flexible multiconductor ribbons preformed approximately in annular form and terminating at each end in a plurality of tersmin al contacts spaced to register with a group of contact termin'als, the terminal contacts at one end of each of the ribbons being electrically connected to a group of terminals of one of the boards and the terminal contacts at the other end thereof being electrically connected to a group of terminals of the other of the boards and each ribbon being of a length to form an U-shaped loop between the boards, the ribbons being substantially equally spaced about the axis of rotation.

PATENTED MIR 3 I9" MULTICIRCUIT ROTARY ELECTRICAL CONNECTOR BACKGROUND OF THE INVENTION The invention has application in electromechanical systems in which it becomes necessary to bridge a rotary mechanical joint with a number of electrical circuits carrying power to sensing information, or both. For example, in conventional gyro systems it is necessary to transmit across the pivots of both the inner and outer gimbal rings power for driving the gyro motor and, in addition, it is desired to transmit a number of sensing and control signals developed by the gyro back across the pivots to the electrical system of which the gyro is a part.

l-lereto fore it has been customary tobridge such rotary joints or pivots by means of conventional slip rings and cooperating sliding brushes or contacts or, in the event the range of relative rotation is limited as in a gyro, by a plurality of individual flexible connectors secured directly to both of the relatively moving parts. The former arrangement has the many well-known disadvantages of sliding contacts such as a relatively high and unstable electrical resistance, a relatively high electrical noise lever, etc. The latter arrangement has the disadvantage of possible failure from fatigue after a relatively low number of operating cycles and requirement of apprecia ble torque for flexing the connectors, particularly where a large number of circuits must be bridged across the rotary joint.

It is an object of the invention, therefore, to provide a new and improved multicircuit rotary electrical connector which obviates one or more of the foregoing disadvantages of prior rotary connectors of this general type.

It is another object of the invention to provide a new and improved multicircuit rotary electrical connector which has one or more of the following characteristics: extremely lowoperating torque; operational over a large number of cycles without failure from fatigue; and freedom from any sliding or relatively moving contacts.

SUMMARY OF THE INVENTION In accordance with the invention, there is provided unitary multicircuit rotary electrical connector comprising a pair of terminal boards of insulation material each having a surface of revolution, means for mounting the boards'for relative rotation with the surfaces of revolution in spaced relation, each of the terminal boards having a plurality of groups of spaced contact terminals arranged approximately in a circle about its surface of revolution, and a plurality of flat flexible multiconductor ribbons terminating at each end of a plurality of terminal contacts spaced to register with a group of the terminal board contact terminals, the terminal contacts at one end of each of such ribbons being electrically connected to a group of terminals of one of the terminal boards, the terminal contacts at the other end thereof being electrically connected to a group of terminals at the other of the terminal boards, the end portions of each ribbon being oriented in the same general direction, and each ribbon being of a length to form an U- shaped loop between the boards with the terminal portions thereof lying on the surfaces of their respective terminal boards, whereby the ribbons are subject to constant flexure at all relative angular positions of the terminal boards. For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description, taken in connection with the accompanying drawing, while its scope will be pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a unitary multicircuit rotary electrical connector embodying the invention while FIG. 2 is a plan view of a preformed multiconductor ribbon for use in the connector of FIG. 1. Referring now to the drawing, there is illustrated a unitary multicircuit rotary electrical connector embodying the invention and comprising a pair of terminal boards of insulation material each having a surface of revolution. Specifically, the terminal boards are shown in the form of a pair of spaced parallel discs 10,11. The connector includes means for mounting the boards for relative rotation with the parallel surfaces in spaced relation. The mounting means may be purely conventional and are not shown although they will be connected to the terminal boards 10 and 11 via the mounting holes 10a, 10a and 11a, 11a, respectively, certain of the mounting holes of the disc ll being omitted for the sake of clarity. Each of the boards 10 and It has a plurality of groups of spaced contact terminals arranged approximately in a circle about its surface of revolution, for example the contact terminals 10b, 10b of board 10 and the contact terminals 11b, 11b of board 11. It is noted that the contact terminals 10b are near the inner radius of the annular board 10 while the contact terminals 11b are at a greater radius, namely, near the outer periphery of the board 11.

The electrical connector of the invention further comprises a plurality of flat flexible multiconductor ribbons 12, 12,

' preferably preformed approximately in annular form as shown in FIG. 2. Each of the ribbons 12 terminates at each end in a plurality of terminal contacts spaced to register with a group of the contact terminals, for example terminal contacts 12a, 12a of FIG. 2. As shown in FIG. 1, the terminal contacts at one end of each of the ribbons is electrically connected to a group of the terminals of one of the boards, for example the terminals 10b of board 10, while the terminal contacts 12a at the other end thereof are electrically connected to a group of terminals of the other board 11. Each ribbon is of a length to form an U-shaped loop between the boards 10 and 11, as shown in FIG. 1, and the'several contact ribbons are equally spaced about the axis of relative rotation of the unit.

As described, it is noted that each of the multiconductor ribbons 12 is subject to constant flexure at all relative angular positions of the mounting discs 10 and 11, the ribbons rolling along the surface of one mounting board and unrolling along the surface of the other, thus requiring a minimum torque during relative rotation of the discs 10 and 11. In a practical construction embodying the invention, it has been found that the mounting boards 10 and 11 may undergo a relative angular movement of :1 from a neutral position.

It is seen that the rotary electrical connector of the invention is very reliable in operation since it avoids all slip rings, commutators, brushes, and the like so that there are no rubbing surfaces to wear or to produce discontinuity of electrical conductivity, particularly under vibration or shock loading.

lclaim:

1. A unitary multicircuit rotary electrical connector comprising:

a pair of terminal boards of insulation material a surface of revolution;

means for mounting said boards for relative rotation with said surfaces in spaced relation;

each of said boards having a plurality of groups of spaced contact terminals arranged approximately in a circle about its surface of revolution;

and a plurality of flat flexible multiconductor ribbons terminating at each end in a plurality of terminal contacts spaced to register with a group of said contact terminals, the terminal contacts at one end of each of said ribbons being electrically connected to a group of terminals of one of said boards, the terminal contacts at the other end thereof being electrically connected to a group of terminals at the other of said boards, the end portions of each ribbon being oriented in the same general direction, and-each ribbon being of a length to form an U-shaped loop between said boards with the terminal portions thereof lying on the surfaces nf flmir "manta...

each having boards, whereby said ribbons are subject to constant flexure at all relative angular positions of said terminal boards.

2. A unitary multicircuit rotary electrical connector in accordance with claim 1 in which said terminal boards are sub.-

stantially parallel spaced discs. 7 I i 3. A unitary multicircuit rotary electrical connector in ac- 

1. A unitary multicircuit rotary electrical connector comprising: a pair of terminal boards of insulation material each having a surface of revolution; means for mounting said boards for relative rotation with said surfaces in spaced relation; each of said boards having a plurality of groups of spaced contact terminals arranged approximately in a circle about its surface of revolution; and a plurality of flat flexible multiconductor ribbons terminating at each end in a plurality of terminal contacts spaced to register with a group of said contact terminals, the terminal contacts at one end of each of said ribbons being electrically connected to a group of terminals of one of said boards, the terminal contacts at the other end thereof being electrically connected to a group of terminals at the other of said boards, the end portions of each ribbon being oriented in the same general direction, and each ribbon being of a length to form an U-shaped loop between said boards with the terminal portions thereof lying on the surfaces of their respective terminal boards, whereby said ribbons are subject to constant flexure at all relative angular positions of said terminal boards.
 2. A unitary multicircuit rotary electrical connector in accordance with claim 1 in which said terminal boards are substantially parallel spaced discs.
 3. A unitary multicircuit rotary electrical connector in accordance with claim 2 in which the groups of contact terminals of one of said boards are at a greater radius than those of the other of said boards.
 4. A unitary multicircuit rotary electrical connector in accordance with claim 2 in which each of said ribbons is preformed approximately in annular form. 